Air-pump



S. S. AVERY.

Am PUMP., APPLICATION FILE'D FEB. i8, 1919.

Patented July 20, 1920.

w//vfsrsfs A TTURNE YS PATENT OFFICE.

SETI-I S. AVERY, 0F PLEASANT LAKE, INDIANA.

AIR-rune.

Specification of Letters Patent.

Patented July 20, 1920;

Application filed Februaryr 18, 1919. Serial No. 277.807.

To all iti/tom?? may concern.'

Be it l-:nown that l, Sarti S. AvnnY, a citizen of the United States,and a resident of Pleasant Lake, in the county of Steuben and State ofIndiana, have invented a new and Improved Air-Pump, of which thefollowing is a full, clear, and exact description. i

The present invention relates to pumps, and while the same pertains moreparticularly to hand pumps for inflating pneumatic tires and the like,the several features thereof are equally adaptable to pumps driven bypower.

One of the principal objects of the invcntion is to provide a singlecylinder pump in which the operation is double acting.

A further object of the invention is to construct a pump in such mannerthat the up-stroke of the piston is limited in its length.

A still further object of the invention is to construct the pumpcylinder in. such a manner that the 11p-stroke of its piston iscushioned by a body of air which is trapped in the top of the pumpcylinder.

A still further object of' the invention is to so construct a pump thatany of the several parts may be renewed from time to time as occasionmay require.

Reference is made to the accompanying drawingsforming a part of thisspecificai tion, in which the figure is a vertical sec tional view of apump constructed in accordance with the present invention.

The ydevice comprises a base 46 which has an interiorly screw-threadedflange 41, with which the pump cylinder 42 is adapted to engage. thelower end of the cylinder 42 being provided with a screw thread 43 forthis purpose. The cylinder 42 is provided near its upper end, with aport or the like, 44, and secured to said upper end is a casting` 45,which is Vprovided with an air passage 46, which in turn is controlledby a valve 47. The upper end of the cylinder 42 is provided with anannular flange 4S. rlhe casting 45 is adapted to be moved intoengagement with the flange 48, and retained in contact therewith bymeans of an annular collar or the like, V49. Clamped between the annularcollar 49 and the flange 48, is a washer 50 and a suitable packing 51,said packing having a downwardly projecting `annular flange 52, thelower portion of which lies within the Vconfines of Y inder be notedthat the port 44 in the side of.

the cylinder 42is at a point remote from the end of said cylinder, thepurpose of which location will be hereinafter set forth.

Mounted for movement longitudinally of' the cylinder 42, is a hollowpiston 55, and screw-thread into the inner end of' said hollow piston 55is a piston head 56, provided with an air passage 57, which iscontrolled by a ball valve 5S adapted to engage against the seat 59.Secured to the outer face of the piston head 56, is a packing 60, saidpacking being secured in place by means of a plate G1 and a bolt 62.This bolt is provided with a longitudinal air passage 63, whichcommunicates with the valve chamber 64 in which the valve is mounted.

Threaded into the outer end of the piston as at 65, is a casting 66,which is provided with an inlet port 67. Projecting from this casting66, is a stem 68, upon the upper end of which is mounted a handle 69.Depending from the casting 66, is an annular flange 70, and suitablysecured to the bottom edge of said annular flange 70, is an air screen71.

Upon the 11p-stroke of the piston 55, fluid is drawn 'into the cylinder42, the uid passing in through the inlet passage 67, through the screen71, hollow piston 55, passage 57, valve chamber 64, and passage 63through the bolt 62. Upon the downstroke of the piston 55, it will beseen that the fiuid will pass around the packing 60. to the space 72between the piston 55 and the cylinder 42, from which space 7 2, thefluid passes through the medium of the passage 46 and nipple 73 to theexterior of the cylinder 42. Upon the up-stroke of' the piston 55, thefluid remaining in the space 72 is forced out through the passage 46 andthe nipple 73, and, at the same time, a new charge of fluid is takeninto the cyl- 42 in the manner hereinafter described.

As above stated, the port 44 which 'leads from the cylinder 42, issomewhat removed from the end of said cylinder and by this constructionit will be seen that as the packing passes said port, it will .beclosed. Upon closing the port 44, a certain amount of fluid will betrapped in the space 74 between the port and the end of the cylinder.The fluidthus trapped in the upper end of the cylinder 42, forms acushion for the i v end ofthe upd-stroke of the piston 55, thusproviding` means b v which the shocks and `jars to which this type ofpump is often subjected, are eliminated. i

Having thus described the invention, what is Claimed is: 'A pumpComprising a base, an internal serew-threaded flange projecting from'the' Vvalve mounted inthe piston head, an in` takeV opening in theother end` of the pis-V ton, a collar carried by the openend of the pumpCylinder and providedrwth an' outlet passage, said collar` having screw-Jhleaded engagement fwith the first-mentioned collar, and a washerinterposed bev tween said collarV and the end of the cylinder, saidwsheiqv forming an air-tight joint between the: cylinder and the hollowpistonV in its movement within the cylinder, substantially asdescribed'. f

Y,s eTH s.. AVERY. I

